Heat the oil in skillet over medium-high heat. Add pancetta; cook until it just begins to brown. Transfer to slow cooker. Add onion to skillet, reducing heat to medium; cook until softened, about 3 minutes. Add garlic, rosemary, parsley, salt and pepper to taste; cook 1 minute. Stir in tomatoes; heat to a boil, breaking up tomatoes. Cook, stirring, until liquid thickens, 2 minutes. Meanwhile, add beans to slow cooker. Pour tomato mixture over beans, stir well. Add just enough water to cover. Cover; cook on low 8-10 hours or on high 4-5 hours.