Unless you're specifically planning a rain team, Hydration is pretty much useless. Accelgor is also too frail to make use of it (usually Vaporen with this ability can stall with Rest).
So Sticky Hold. It'd prevent Rotom or Sableye from using Trick on you, at least. The frequent use of Accelgor is giving it a Focus Sash and letting it set up Spikes.
Hydration: heals status problems if it is raining
Sticky hold: prevents your enemy from stealing your item.
i take hydration becaus I don't know any trainer with an item taking move.
hope this helps : sorce cerrebii