PTNoge saidBut, when choosing DL's for a split day workout, they are best performed with legs, rather than back day because of the dynamic movements involved in the exercises. In addition, Squats and DL's are a great pairing.
That might be fine if you are doing a body part split wo wherein you only do 1 day for legs. If you are doing an upper/lower split, I'd prefer to do squats on 1 lower day and DL's on the other. Or if you are doing a 3X wo (e.g. mon, wed & fri), as I'm currently doing, then best to do squats on 1 day (e.g. mon) and DL's on the 3rd wo day(e.g. fri).
While it is possible to do both in the same wo, both squats and DL's are pretty exhausting. DL's are more like a full body exercise. Between the two the exercise that is done second will be at the expense of the former. If you want to maximize these exercises, then separate days are suggested.