The statement "Tertib merupakan rukun solat yang ke-13" is true. In Islam, there are five pillars of faith, and one of them is performing the obligatory prayers or solat. Tertib, which means order or sequence, is an essential aspect of solat. It refers to the proper sequence and arrangement of the actions and movements during prayer, such as standing, bowing, prostrating, and sitting. Following the prescribed order and sequence is necessary for the validity of the prayer. Therefore, tertib is considered the 13th pillar or rukun of solat.