As far as bullies go, it's up to you to scare them off, teachers don't care. I was once given a lecture because I asked a teacher to help before things got physical.

As far as violent teachers? once someone lays hands on you you've got the right to fight them off as much as you need to, to get yourself out of the situation. Most classrooms have one door, and if it comes to it as long as the teacher strikes first and is between the student and the door... yea.

Above all, Vorpal was right, be the one they fear. I was lucky, my last name translates to assassin in Italian, and the mob is still scary enough that people made asumptions and left me alone for the most part. Figure out who else is being picked on, and if they don't want to be friends sugest you guys stick together for safety in numbers at the least. When I did get picked on I had one of the biggest guys in school backing me, along with a few other people and that's probably what saved me a lot of troubble when people realized my name's just a name. If you can pull off something like that you'll be better off till you can get out of there.