Richard Starkey.
For example: http://solobeatles.com/2012/12/11/georges-original-version-of-it-dont-come-easy/
Whatever the real story, Harrison had at least as much to do with writing the song as Ringo. Even in the "official" version of events, Ringo only wrote the lyrics to the first verse, Harrison wrote, arranged, and produced the rest.
Personally, as much as I like Ringo, it sounds like and probably was originally a Harrison song.