If you mean the Psyduck that sit in your way, you need to get the Secretpotion from Cynthia, then go to Solaceon Town (the Daycare one) and go north to the Café. The Psyduck will be next to the Café.
There are Pokemon Centers in every town/city.
solaceon town has a daycare in Pokemon diamond and pearl
it is colse to soaceon town .
There is no "Foggy city" in Pokemon Pearl it is a route celestic town you can use defog ( a hm when you beat the 4th ) to get rid of the fog.
There are two choices: by snowpoint city by celestic town
sunnyshore city if you have palkia
you go through hearthome city and it will be the umcoming one in the next town........
you first have to go to floaroma town and then you can go to eterna city
sandgem town/jubilife city...um who posted that question?
East of Hearthome city and south of solaceon town
North then East of Twinleaf Town and South of Jubilife City.
There are two places to get it. Snowpoint city Celestic town