(a) No person may be tried, convicted, sentenced, or punished for a crime when by reason of mental illness or defect he is unable to understand the nature and object of the proceedings against him, to comprehend his own situation in reference to the proceedings, or to assist in his defense in a rational or reasonable manner. This condition is hereinafter referred to as "incapacity to proceed."
(b) This section does not prevent the court from going forward with any motions which can be handled by counsel without the assistance of the defendant.