Clear all the jelly is the goal to finish level 13 in Candy Crush Saga. In this level the jellies are mostly in the middle part and there are some holes in the middle so clearing them is a bit challenging. You only have 21 moves to finish this level, so you should use them wisely.
The strategy here is simple. look for matching candies inside the jelly. Always look for special candies and chocolate balls in the game. Use them when you think you're going get more jellies. Keep doing it until you get all the jellies. If you're lucky, you might finish this level with more moves left for Sugar Crush.