Hey, yes, there's italian dubs for all episodes, which is how I watch them, I don't hear the original voice in the background, columbo himself has been dubbed by 2 actors: one for all episodes until season 9, then another one following the former actor's death, they had such a similar voice that I didn't even know they were 2 actors till now.
The only exception was ransom for a dead man, which was with a different actor, much different voice that episode.
And you, do you watch it in the original language?
When I was a child I could watch it only in TV, an unfortunately we have a lector guy (which I think is not po****r in other countries), so that means: you hear the background, the original voices of the actors (so at least I could hear how Peter Falk actually sounds like), but it is covered by one guy who reads all the characters (no matter if men or women, children or adults - only one guy is reading for everyone). I always wanted to watch in original with subtitles. When I was older and changed my living country I managed to buy a box of DVD with original voice (there were no subtitles in my language) so now I watch it in original English with English subtitles. Which is definitely the best for me and since then - I discovered a lot of new things in Columbo :)