Yes, you can, and you should. The V713 subdirectory contains service items, maintenance you applied, for NetView 7.1.3.
If you have installed 7.1.4 over that, then it can be deleted.

But you need to do much more than just that. It is dangerous to run so close on space in NetView. If you don't have enough filesystem space when the map and database updates are made, for example, then the databases may become corrupted when the daemons try to write it them out to disk. You could easily end up have to delete everything and rediscover. It is recommended that your average space in /usr/OV be only about 80 percent utilized to guard against this.

James Shanks
Level 3 Support for Tivoli NetView for UNIX and Windows
Tivoli Software / IBM Software Group