Digital clock

Dear friends I am trying to make twelve hour system digital clock using 7490 counters.I have completed second hand and minute hand but I am confused to make the hour hand since after the twelth count it should count from 01.can anybody provides me idea how could I do this.I will grateful for your help.

Thanks a lot for your help but in this projects you r using three types of counter but I am trying to dothis by using only 7490 decade counters.if you have any idea about it please help me.i will be grateful for your help.