Are you including Kentucky parts of Cincinnati? How much does that push it even more into the conservative camp compared to just including the Ohio side?
The Cincinnati metro includes parts of rural Kentucky and Indiana, as well as suburban areas in Kentucky. With just Hamilton and the three main suburban counties in Ohio, it looks like this:
Romney: 439,271 (55.2%)
Obama: 345,682 (43.4%)
So suburban Cincinnati in Kentucky does move it to the right a little bit. Not much though. And the rural counties, including the one in Ohio, barely do anything.