Step 1 Heat the olive oil in a large Dutch-oven style pot over medium-low heat. Add the onion, celery and carrot and cook gently until the vegetables are tender, stirring often, about 6 to 8 minutes.
Step 2 Season the duck legs with salt and pepper and add to the pot. Saute on both sides (about 15 minutes) then add 1 teaspoon salt, one-fourth teaspoon pepper, the wine, tomatoes, bay leaves and rosemary.
Step 3Bring to a simmer and cook covered over low heat 1 to 1 1/2 hours, until the meat is very tender. Check and stir often to avoid burning.
Step 4Remove the duck legs from the sauce and cool. Remove and discard the bay leaves and rosemary. If the sauce is still too liquid, uncover and cook down to sauce consistency. Skim and discard oil from the surface of the sauce. For a rustic sauce, leave it as is, or blend in a food processor until smooth.
Step 5Remove the skin and bones from the duck legs and gently tear into small pieces. Add the meat back to the sauce. Adjust seasoning and keep warm.
Step 6To serve, cook the pasta al dente, drain and if desired, stir Parmesan cheese into the pasta, then mix with the sauce and serve.