In MTG, can I use Stave Off to save my creature from Oblivion Ring?
Sure you can.  Oblivion Ring comes into targets "another nonland permanent" - your creature.  With this triggered effect on the stack, cast Stave Off in response targeting your creature, giving it Protection from White.  The Oblivion Ring's ability will now be countered by game rules, due to having an illegal target.

What you can't do with Stave Off is bring back a creature that has already been exiled by Oblivion Ring.  The creature is far from the battlefield and can't be targeted; even if it could, it is too late for Protection from White to help it!  You'll need something capable of getting rid of an enchantment to rescue your creature from oblivion in this case.