Uncivil Unrest

Riot is a replacement effect. Players can’t respond to your choice of +1/+1 counter or haste, and they can’t take actions while the creature is on the battlefield without one or the other.

If another effect (or effects) modifies how much damage your creature with a +1/+1 counter on it would deal—by preventing some of it, for example—the player being dealt damage or the controller of the permanent being dealt damage chooses the order in which any such effects (including Uncivil Unrest’s) apply. If all of the damage is prevented, Uncivil Unrest’s effect no longer applies.

If you choose for the creature to gain haste, it gains haste indefinitely. It won’t lose it as the turn ends or as another player gains control of it.