Section 20. The time and place of the commission of the crime need not be alleged unless it is an essential element thereof. The allegation of time in the caption shall, unless otherwise stated, be considered as an allegation that the act was committed before the finding of the indictment, after it became a crime, and within the period of limitations. The name of the county and court in the caption shall, unless otherwise stated, be considered as an allegation that the act was committed within the territorial jurisdiction of the court. All allegations of the indictment shall, unless otherwise stated, be considered to refer to the same time and place.