Dewott is a new water type pokemon in Pokemon Black and White. Dewott evolves from a Oshawott at level 17, and into Samurott at level 36.
Dewott is only attainable from evolving the starter pokemon Oshawott, which can not be caught in the wild.
If you want all three starter pokemon and their evolutions, you’ll need to get to the first pokemon center where you can trade pokemon. Trade your starter, then restart your game. Do this process twice picking different pokemon. On your third restart, have all of your starter pokemon traded back and you’ll have all three starter pokemon.
