Deep techno
I feel it is slighly worse to call someone a "failed clown", than to call them "a clown". Some people like being the center of attention however - I think this girl does. I think she may also feel quite insecure about herself, and so she's trying to push herself up in the eyes of the class by pushing you down. It's pretty common at school, to get up the pecking order, some people have to peck others down it. Aspies and NT's come into conflict a lot about this. Aspies are easy to peck because they don't even notice the pecking order or don't care where they are on it.
So you can just tell her, "you don't like how loud and disruptive she is, and you think she is really insecure, immature and a bully for picking on you".
Sometimes the smartarse come back is the only way to deal with these kids. They won't ever like you but they will start to leave you alone, because picking on you is humiliating.
However a better way of dealing with this, is not to make comments to the teacher about her where anyone else could possibly overhear. Ideally no comments at all. Consider the annoying behaviour a sign of low intelligence and debilitating insecurity on her part, and feel sorry for her, but don't try to help her. Try to ignore it. If she attacks you directly, say something to the effect that you feel sorry for her because she thinks she can't get ahead in life without being an immature bully. Don't let her bluff you into tears. No reaction is best. Tell her you don't place any importance on what she thinks, and walk away - ignore her.
The calmer you can remain the better. If you get really upset that just gives people like her ammunition to make their case. So think of her as a short lived bacterium, and consider that when you finish school she is not going to matter at all. What ever you have to tell yourself to feel calm - do it.