Which food takes the longest to digest in the stomach?

If we talk about the human stomach, then pork meat and various legumes are digested in it the longest. So, it is better not to eat such foods at night, otherwise your stomach, instead of resting, will digest these foods. But, for example, a watermelon in the human body is digested for only twenty minutes. But potatoes are digested in the body for only sixty minutes. But it’s not worth eating it overnight, because it is a starchy product.