Can I bring a lawyer to my California small claims hearing?

Not into the hearing room itself. Code of Civil Procedure section 116.530 specifically bars attorneys from representing either side at a small claims hearing, plaintiff or defendant alike.

You're free to consult with a lawyer beforehand to prepare your case, and plenty of people do exactly that. What makes this restriction meaningful is that it's the one civil court setting in California where being unrepresented doesn't put you at a structural disadvantage against a party who can afford legal counsel, since neither side gets one at the hearing itself.