How do you best defend yourself if attacked by a pitbull or presa canaria?

Excuse the negative focus in this question.

But since I became a parent, I’ve been occupied trying to find the best approach if being attacked by murderous dogs.

If I’m alone, without my kid, then I guess the best advice, after all, is to try and put your legs on your back and run. But now, more often than not, I’m in a different situation, where I couldn’t just flee.