Legal Question in Civil Litigation in California

Under some circumsances yes, but generally you wouldn't want to. All it would do is make it possible for a larger judgment to be entered against you. If you have a cross complaint that is for more than the jurisdictional limit of small claims, you can file that cross-claim along with papers to move the case to the proper jurisdictional level. If you don't have a cross-claim, then you are probably better off having the case heard in small claims and then appealling it to the Superior Court - Limited Jurisdiction if you lose.