There has been a lot of discussion of Texas's delegate situation, which favors Obama, but not so much about Ohio's. These two links give a good idea of the situation there.
http://www.buckeyestateblog.com/ohio_primary_analysishttp://www.ohiodems.org/site/c.mhLRKZPCLmF/b.3909931/It looks like the delegate situation is more evenly divided than Texas as far as benefits to the candidates. The main thing to watch out for is even numbered districts- if there are 4 delegates in a district, a candidate needs 62.5% of the vote to avoid a 2-2 split, and if there are 6 delegates in a district a candidate needs 58% of the vote to avoid a split.
So if you're Obama you don't want to see one of your better districts have an even number of delegates, and that's the case with some of his better districts such as CD-15, home to Ohio State, and CD-1, home to Cincinnati. On the other hand, Hillary has some strong even-numbered districts such as CD-14 with 6 delegates likely to split 3-3.
Obama has an 8-delegate majority black district which includes eastern Cleveland - CD 11. The best Hillary can hope for here is a 5-3 split and a 6-2 split may be more likely. So this district looks to be a strong Obama bulwark against Hillary getting a big delegate lead out of Ohio. Obama's overwhelming lead among black voters will make the even-numbered nature of the district irrelevant.