If you're referring to how they placed in sub-district and how they will be placed in districts, then the 5th placer will be put in the 4th place spot. For example, if the north has 3 and the South has 5, then the South 5 place will be put in the North 4th place.
Just to clarify - the rule on how wrestlers advance from subdistrict to the district tournament is a district level decision. Depending upon which district you are from, the answer might be different. If you are in doubt, you should check with your club director, who should know what your district's rules are.