Are you paying or receiving the support?
You can contact the CSEU and request that a modification be done to the order. You can show them that the child is enrolled in college and you can request that the support continue. If it is allowable in your state, they will draw the paperwork up and present it to the judge. Who will decide if support will continue and what amount of support it will be. If it isn't, they will inform you of that to.
In some cases, you will have to show that the child is registered in college (there may even be a set amount of hours that they have to attend a semester). You have to show that the child is still your dependent. They live under your roof (no dorms) and that you are providing the necessities for them (food, clothing, shelter, etc.)
You can ask for the ex to pay for a portion of the college expense also. If you are going back for a modification to the support order, you can ask for anything. The judge will determine what or if you will receive it.
Good Luck!
Ambr