> He won the election in the most corrupt country in Europe.

He won by a landslide regardless of corruption (if there ever was one during those elections). Everyone was fed up with Poroshenko, and Zelensky was seen as a new wave, young politician who will bring change (on top of his popularity as a comedian).

> he suspended the next election and no more elections have been celebrated ever since.

By "he" you mean constitution of Ukraine?