From Public Policy Polling:
PPP’s first post-conventions poll in Ohio finds Barack Obama with a 5 point lead over Mitt Romney, 50-45. This is the largest lead PPP has found for Obama in an Ohio poll since early May. Last month Obama led 48-45.
Obama’s leading in Ohio because he’s not as weak there with some large voter blocs as he is in other states. He trails only 48-46 with men and 50-46 with whites, and actually leads 49-47 with seniors. His performance with those groups is far better than it is nationally- Romney would need much wider leads with them if he was going to take Ohio.
Partisan breakdown of the poll is 41 percent Democrat, 37 percent Republican.
PPP also has Obama at 49 percent in North Carolina, while Romney is at 48 percent. The partisan breakdown of that poll is 47 percent Democrat, 34 percent Republican (in 2008, Democrats had an 11-point advantage over Republicans in the state).