Bigger question is... why wouldn't those play in the default media player at all? ...are you downloading mp3 versions of those podcasts, or are you downloading them as ogg files?

It would probably be simpler to just add ogg support to your tablet than it would be to re-engineer the gpodder db to be any less efficient by storing a whole new field per podcast just for what player to use. Not to mention, it is simpler and intuitive not to do that, I would think. Plus--it wouldn't actually fix your problem. It would just add a more complex band-aid. It would work--but I would think we're all going to give up a smidgen of performance for something that's better off being fixed at the player side.