What kind of roast do you have?
If you make it in your dutch oven, it will be a pot roast. A pot roast is usually made with sauce and veggies cooked with it (similar to a beef stew).
If you want roast beef that would be medium or medium rare inside, you should cook it in an open pan.
"If you want to make an apple pie from scratch, you must first create the universe." -Carl Sagan