Trump carried Ohio by nearly ten points, and his approval rating is noticeably higher in the Buckeye state than in the US as a whole (though still slightly negative). So, naturally many people have speculated that this is one of the GOP’s best opportunities for a pickup. However, the betting markets seem to disagree, with Democrat Sherrod Brown firm favourite to retain his seat. Betfair offers 1.36 (73.5%) on the Democrats, while you can get 4/11 (73.3%) with Paddy Power.
In this case, I think the betting markets are even underestimating Brown’s chances. He has a relatively strong net approval rating and is a seasoned campaigner, having fought off a strong Republican challenge six years ago. He has led every poll that has been conducted so far, by margins ranging from 4 to 13 points. Some of the polls have him winning more than half of the vote, a sign of strength. So I suggest that you take Paddy Power’s odds on him being re-elected.