I tend to do deadlifts and stiff leg deadlifts on leg day. I'll start with squats first, then move to deadlifts, then to stiff leg deadlifts to focus on the hamstrings and glutes. Careful though - gauge how your lower back feels. If it feels like too much for you, don't push it.
Sometimes, I'll do deadlifts (not the stiff leg deadlifts) when working the back. But doing this on a consistent basis is probably a bit much for the lower back if you do squats or stiff leg deadlifts on leg day as you'll be seriously taxing your lower back on both leg and back day. It might not give your lower back enough time between to recover fully.
The deadlift is a unique exercise in that it works legs, glutes, back, abs, and pretty much all the other muscles as well to a lesser extent. Give it a try and let us know how it works for you.