In Scrum there is no designated leader in a management-hierarchical sense within the team. That means, there is no single person telling you to do Task X and to do it in Time Y. These things are decided upon by the team as a group. This way every developer is responsible, himself for his work. He estimated the time it will take, himself, he is responsible for completion, himself. Of course that also means that he takes the blame, himself if things go wrong.
In tradition models that would not be the case. There would be a team, with a designated leader who is responsible for every aspect of decision making. He would tell developers to do tasks, and he would tell them how to do it and within what time. However he would also be the one who takes the blame for everyone on the team.
This does not mean, however that teams can't have leaders in Scrum. You still need somebody with merging privileges and who has an overview of the whole project. Basically somebody who has the last say about architectural changes that could possibly affect the big picture and so on. That guy usually is the team lead. Very often, officially so.
In fact I've never worked in a Scrum environment where there was no official Team Lead. Looking at it from a pragmatic point of view, I'd actually have some issues with working in such an environment: My Team Lead is the guy who merges, he's the go-to guy for architectural problems. If there is to be an API change, we discuss things and he makes the decision.
- Without a team lead, what if there's two guys not agreeing. Who is right?
If there are meetings concerning future developments or pretty much anything, he's the one who goes, keeping my back free to do my actual work. If decisions that were made in such a meeting seem strange, or not good, there's still Daily/Retro/Task Planning where you can raise your concerns.
- If there is no Team Lead, then who is going?