Ash's doesn't have a dewott. He has an Oshwott, and it has yet to evolve.
Ash's hoot hoot evolves at episode 183
Dewott
Ash's monferno will evolve into infernape at lv.32
Ash's Swadloon evolves into Leavanny in the episode titled "The Battle of the Samurai," which is the 19th episode of the Pokémon Black & White series. In this episode, Ash and his friends encounter a Pokémon battle involving a Samurai and his Leavanny, which inspires Swadloon to evolve during battle. This evolution signifies Swadloon's growth and strength as a Pokémon.
Dewott is a water type Pokemon that envolves into Samurott, a Pokemon that has the body style of a Arceus, and has a horn like a Cobalion
Osawott Evolves into dewott at level 18
Ash's Snivy didn't evolve yet.
episode 1337
The Episode Number in which Ash's Staravia evolves into Staraptor is Episode 586.
345
Episode 87
Ash's hoot hoot evolves at episode 183
Dewott evolves at level 36.
Dewott evolves into Samurott at level 36.
episode 586 season twelve
samurrot
Ash's cyndaquil doesn't evolve until Sinnoh, in the Sinnoh League Victors series. The episode is called An Old Family Blend!