yes you can take as many exam you can. In the last you have to choose one in which you want to join. There is no limit in how many number of exam you can take. There is limit that you have to join in one college only. if you leave college without admission then you have to pay penalty for it and notify college that you are leaving the seat.
eligibility criteria for CLAT is 45% for general category and for ILSAT is 50% for general category.
Hope it helps!