Pasta with Confit Duck and Savoy Cabbage

Name: Pasta with Confit Duck and Savoy Cabbage
Ingredients: 1/2 teaspoon vegetable oil; 3 (6- to 8-oz) confit duck legs; 2 large onions, halved lengthwise, then sliced (1/4 inch thick; 4 cups); 1 teaspoon salt; 1 (1 1/2-lb) piece Savoy cabbage, cored and cut into 2-inch pieces (8 cups); 1/4 cup dry white wine; 1 1/2 cups reduced-sodium chicken broth (12 fl oz); 1 lb dried campanelle (bell-shaped pasta) or garganelli; 1 tablespoon unsalted butter; 2 tablespoons chopped fresh flat-leaf parsley; 1/2 teaspoon black pepper