Hmmm, I only know what I have seen on ownage thread. Current Asgard would lose imo. Classic Asgard would win. I guess I should say pre and post Ragnarok. Asgard is a shade of what it once was. There is no Odinson, Odin was in his prime and ripping Universes out of the World Tree and shaking Galaxies. Yeah, I feel pretty confident ( and a little sad) that current Asgard would not be capable of waging a proper war right now.
not sure how many gods the olympians could call on. sheer numbers could be a problem for olympus. zeus and odin, whatever odin, would be a draw i've no doubt, or close enough not to matter. but asgard would just drown them in numbers, unless the amazons were allowed to fight for zeus. then it would be a battle--a good one no doubt. you'd have to try and match up the top gods of asgard with the top gods of olympus to get a better sense of who would win.