They didnt start on the pod though. They start on flat ground in a room next to the Senate Pod if I recall correctly - a room that gave neither competitior an advantage. It was either Yoda's foolishness or Sidious' skill that forced them on to the pod. But the fact is it started neutral and ended in Sids favour.
Well going by the movie, you see both of them igniting their lightsabers and then jumping onto the pod. Then they start fighting. So obviously somebody must have pressed the elevate button. And it really end in a stalement, I mean, Sidious won because Yoda had little space in pod to cling onto it and thus fell like 60 ft.