Anna in the 1850 census is his wife, short for Rosanna or Rose Anna, or with other spellings, Walker. I don't know about a wife Mary, as I am descended from Rosanna, born 1815 Ohio. If I remember correctly, they were at separate addresses in the 1860 census, and they may have divorced. She died or remarried between 1860-1870, as she disappeared from the census.
John C. Death was b.1812 in Warren Cnty, Ohio, and died 1880 in Fountain Cnty, Ohio. As Mary died in 1809, either they didn't marry or something is wrong with her record.
Wonder whether there could have been more than one John C. Death. Seems unlikely, but some of these dates just aren't making sense, are they?
I'm sorry, I posted the above. This is not the same John C. Death, as mine was born 1812, considerably later that the one in the census above. I didn't realize that there were two with the same middle initial.