If there is no restriction mentioned below the table (like max. 3 h) it means the default limitation applies, which is 1.5 hours, starting from the time that you have set on the blue clock (made of paper). You are supposed to place this paper-clock behind the windscreen, showing the "time" of your arrival. (after X h :30 minutes and before X+1 hour : 00 mins you should set X+1:00.
After X h : 00 mins and before X h : 30 mins you should set X h: 30 mins, as time of arrival on this clock).
So if you arrived at e.g. 15:23, you can set 15:30 on the clock and stay till 17:00. If you arrived at 13:01, you can set 13:30 and park till 15:00.
So in the best case you can park for almost two hours.