After what gym do you catch ponyta in platinum?

You can catch Ponyta in Pokémon Platinum after you defeat Gym Leader Crasher Wake, the Water-type Gym Leader in Pastoria City.

This is because Ponyta is a Fire-type Pokémon, which is strong against Water-type Pokémon. After defeating Crasher Wake, you can find Ponyta in the grasslands of Route 211.