If you're only gonna do one leg excercise (which I don't get anyway; if you're gonna do one, might as well do a proper leg workout, but that's up to you), then it should be squats or deadlifts.
you need to throw down with some squats. ideally, you shouldn't lag on particular body parts, namely legs, and your lower back. but whatever floats your boat.
Leg training is paramount.It is the stimulus for growth in your entire body.If you don't wish to add squats to your routine, try deadlifts while standing on a platform or other raised surface.These hit the legs just as well as squats do.