Romney's up at the moment in Ohio by several points, but the rural counties aren't in yet. From Nate Silver at the NYT:
Mitt Romney leads Rick Santorum by about 6 percent in Ohio based on the precincts that have reported so far. However, this vote is in some of his strongest areas, and the margin should tighten as more rural areas report.
About 60 percent of the votes tabulated so far are from Cuyahoga, Franklin and Hamilton counties, home to Cleveland, Columbus and Cincinnati, respectively. But only about 20 percent of the votes in the Republican primary in 2008 was cast in one of those counties, meaning it the current vote count is disproportionately weighted toward these areas.