The closest thing to a crossover event where Marvel and DC characters face off is the "JLA/Avengers" series (1997-1998). This story is about the two teams working together to prevent an alien invasion, and it doesn't involve a decisive victory for either side.
There are also "Marvel vs. DC" video games, but these are non-canonical and do not represent a definitive "winner" for either universe.
It's important to remember that Marvel and DC are separate companies with their own unique characters and stories. While fan debates about which universe is "better" are common, there is no official victor in a "Marvel vs. DC" scenario.