Between a helicopter and an airplane, which requires more power to fly, for a given TOW?
Airplanes fly by creating lift from their wings. This causes some drag, but good wings have lift/drag ratio's in the range 15-20. That means the lift-dependent drag is only 5% of the lift. Helicopters on the other hand generate lift directly from trust; there is no multiplier involved.

E.g. a 4000 kg plane will have a weight of 40.000 Newton, so the drag incurred will be 2000-3000 Newton. A 4000 kg helicopter will need to produce 40.000 Newton of lift just to hover. 

Of course, planes and helicopters both have additional drag from forwards airspeed, and for planes this is obviously unavoidable to prevent stalls.