PEN §1025: (a) When a defendant who is charged in the accusatory pleading with having suffered a prior conviction pleads either guilty or not guilty of the offense charged against him or her, he or she shall be

(a) When a defendant who is charged in the accusatory pleading with having suffered a prior conviction pleads either guilty or not guilty of the offense charged against him or her, he or she shall be asked whether he or she has suffered the prior conviction. If the defendant enters an admission, his or her answer shall be entered in the minutes of the court, and shall, unless withdrawn by consent of the court, be conclusive of the fact of his or her having suffered the prior conviction in all subsequent proceedings. If the defendant enters a denial, his or her answer shall be entered in the minutes of the court. The refusal of the defendant to answer is equivalent to a denial that he or she has suffered the prior conviction. (b) Except as provided in subdivision (c), the question of whether or not the defendant has suffered the prior conviction shall be tried by the jury that tries the issue upon the plea of not guilty, or in the case of a plea of guilty or nolo contendere, by a jury impaneled for that purpose, or by the court if a jury is waived. (c) Notwithstanding the provisions of subdivision (b), the question of whether the defendant is the person who has suffered the prior conviction shall be tried by the court without a jury. (d) Subdivision (c) shall not apply to prior convictions alleged pursuant to Section 190.2 or to prior convictions alleged as an element of a charged offense. (e) If the defendant pleads not guilty, and answers that he or she has suffered the prior conviction, the charge of the prior conviction shall neither be read to the jury nor alluded to during trial, except as otherwise provided by law. (f) Nothing in this section alters existing law regarding the use of prior convictions at trial.