The amount of time your pork tenderloin will take to finish cooking in the Dutch oven after searing will depend on the size of the pork, how cooked it got during the searing process, and how hot your oven is. Even the type of Dutch oven could affect the cooking time. So, I recommend either using an oven-safe alarm thermometer (that beeps when the target temp is reached), or checking the pork every couple minutes after the minimum cook time listed in the recipe to make sure it doesn't overcook.