Thanks for your reply. I don't know how old he was, in fact I don't even know for sure that he was still alive. He had a son Robert born in 1797, so he would probably be at least in his 70's. However, another person replied to my message and said that the Hugh in the census was 51, so he isn't the one I'm looking for.
I know that Robert and his family were in Ohio in 1850, but I haven't been able to locate them. (There were more than 20 Roberts in the 1850 index, all the wrong ones.) I was hoping that I might find him living with his father, but so far that looks like a dead end.