WESTERVILLE, Ohio — Don’t rush Ohio’s undecided voters. They still have a few hours to pick between Barack Obama and Hillary Rodham Clinton before Tuesday’s primary.

As Ohio barrels toward its primary, the two Democrats’ campaigns made eleventh-hour appeals to undecided voters on Sunday. The pair dispatched volunteers to go door-to-door to persuade holdout voters in a tightly contested race.

‘‘Ultimately, it comes down to the choice you make as to who you want to hire,’’ Clinton told supporters before they went knocking on doors in this Columbus suburb. ‘‘Many of you have made up your minds, but I know there are a lot of people who are still trying to make up their minds.’’

About one in 10 voters remain undecided, according to a (Cleveland) Plain Dealer poll released this weekend. Clinton posts 47 percent support to Obama’s 43 among likely Democratic voters, a statistical tie.

And there’s still time to talk to voters, whose support is pliable and whose eyes are looking for the differences.

‘‘I know it’s two days before the election. This is your chance to lift the hood and kick the tires,’’ Obama told these suburban voters hours after Clinton stopped nearby. ‘‘Some of you may be undecided and still trying to sort out who you’re voting for.’’

Obama-supporting Candice Swords gave Clinton another look on Sunday. She’s still supporting Obama, but wanted to be sure.

‘‘I’m a huge Clinton family fan,’’ said Swords, who saw Clinton speak in the morning, listened to Obama during the afternoon and knocked on doors for Obama in the evening. ‘‘My daughter, Chelsea, is named after Chelsea Clinton. She’s pulling for Hillary, but she’s not old enough to vote.’’

Voters listened to both, looking for some last-minute guidance.

‘‘I’ve been watching all the debates on TV and initially I thought Hillary was the one I’d vote for, but lately she’s been taking the campaign a little more lightly than Barack has,’’ said James Bourget, who visited Obama’s event and remains undecided.

‘‘I think they’re both good on the issues, but I’ve been really turned off by Hillary’s performance in the debates lately. I kind of liked her initially. She’s been catty, unprofessional. Complaining about the whole thing getting the first debate question — suck it up and answer the question. What’s the big deal?’’

Clinton complained about unfair treatment at Tuesday night’s debate in Cleveland. She said she found it unfair that she always got the first question and Obama has received a lighter level of scrutiny, a theme her aides have hammered in recent weeks.

Clinton has lost 11 consecutive nominating contests and trails Obama in nominating delegates. Her campaign has made Ohio and Texas make-or-break states that could be the end of her once-frontrunner campaign. With 141 delegates up for grabs in Ohio, a strong showing here could give her camp a much-needed shot of momentum.

‘‘Well, I’m kind of torn. I’m African-American, and it’s like Barack is the first person who has a chance to really become president. I think I should be voting for him, because that would be historical,’’ said Teressa Mitchell, a University Heights voter who went to see former President Bill Clinton speak Saturday in the Cleveland area. ‘‘But, you know, she’s qualified also.’’

The level of last-minute voter indecision is typical for most elections. Four in 10 voters decided in the last week of 2004’s Democratic primary campaign, according to exit polls. On the last day, 16 percent decided — and that primary, relatively speaking, didn’t count for much because John Kerry already had a lock on the party’s nomination.

In 2000’s Republican primary, 15 percent decided during the last 72 hours who to support, even though then-Texas Gov. George W. Bush had clinched the nomination.

With Ohio playing a key role, turnout is expected to be high. Secretary of State Jennifer Brunner said Friday she expects 55 percent of voters to cast ballots, about 20 points higher than 2004’s primary.

Many voters, though, are waiting.

‘‘I can get a lot of information in 48 hours,’’ said Westerville voter Becky Mallott, who remained undecided after attending a Clinton event Sunday and planned to stop at the later Obama rally.

‘‘I like them both for their personalities. I’m a Democrat at heart, so I’m comfortable with both of them. I’m just waiting to see the differences. There aren’t big ones, that’s why I have to listen carefully and study hard.’’

She has until the polls close Tuesday at 7:30 p.m.