It depends how hardcore you play the games.
On the surface LoL focuses a lot more on teamwork. The characters are slower, the spells have low cool down and the stuns are MUCH shorter than DotA. This means that catching a person off guard usually requires more than one person to gank them. In DotA, you still have teamfights, but overall it's less engaged than with LoL. A hero can more easily tumble out of control and most pubbies tend to do the one man carry kind of thing. If you are really hardcore into the game, like 4-8 hours daily into a game, then they are both exactly the same more or less. Team games always revolve around teamwork. In most pro-level play, the difference in mechanics between is much less important to the distribution and understanding of duties.