A complete record of all proceedings and testimony before the commission or any commissioner on any formal hearing shall be taken down by a reporter appointed by the commission, and the parties shall be entitled to be heard in person or by attorney. In case of an action to review any order or decision of the commission, a transcript of that testimony, together with all exhibits or copies thereof introduced, and of the pleadings, record, and proceedings in the cause, shall constitute the record of the commission, but if the petitioner and the commission stipulate that certain questions alone and a specified portion only of the evidence shall be certified to the Supreme Court or the court of appeal for its judgment, the stipulation and the questions and the evidence therein specified shall constitute the record on review. The provisions of this section shall not apply to hearings held pursuant to Section 1702.1.