Vegetarian Baked Ziti

Name: Vegetarian Baked Ziti
Ingredients: 6 ounces uncooked ziti pasta; 1 tablespoon olive oil; 1 1/2 cups onion chopped; 2 cloves garlic minced; 1 large carrot, finely chopped; 1 (14.5 oz) can tomatoes with no added salt; 1 (8 oz) can tomato sauce; 1 cup mushrooms, sliced; 1 1/2 teaspoons dried oregano; 1 can (15.5 oz) great northern beans, drained and rinsed or other 6 ounces ricotta cheese (part-skim or fat-free); 3 ounces reduced fat monterey jack cheese, shredded or 3 tablespoons grated parmesan cheese