Hanging a dish towel from an oven door makes sense -- the towel is always at the ready, and the oven's warmth quickly dispels dampness. Here's a way to improve on the idea, keeping the towel from slipping off:
Make it into a loop by attaching Velcro strips to two ends, one on the front and one on the back, below. Stitch in place, or use iron-on Velcro strips.