Preheat oven to 350 degrees F. Sprinkle cavity of duckling and rub outside of skin with marjoram and pepper; stuff with orange wedges and celery. Skewer neck skin to back of bird; tie legs to tail using 100-percent-cotton string. Twist wings under back. Prick surface with a fork. Place duckling, breast side up, on a rack in a shallow roasting pan. Insert a meat thermometer into thigh. (Do not touch bone.)
Roast duck, uncovered, for 1-1/2 to 2 hours or until thermometer registers 180 degrees F, drumsticks move easily in sockets, and juices run clear. Discard hot fat as it accumulates. Place parsnips and quinces or apples alongside duckling on the rack, during the last 45 minutes of roasting.
Meanwhile, for glaze, halve pomegranates. Using the tip of a spoon, remove 2 tablespoons of the pomegranate seeds; set aside. Squeeze remaining pomegranates with a hand juicer. You should have about 1/2 cup of juice. (Or, substitute 1/2 cup cranberry juice.)
Combine pomegranate juice, jam, apple cider or juice, soy sauce, and lemon peel in a medium saucepan. Bring just to boiling. Reduce heat and simmer, uncovered, 15 minutes or until reduced to 1-1/2 cups, stirring frequently as mixture thickens. Strain through a sieve over a bowl.
Baste duckling with 1/2 cup of glaze the last 15 minutes of roasting; reserve remaining glaze. Cover duckling and let stand 15 minutes. Transfer duckling to platter. Surround with herbs and fruit, if desired.
To serve, carve duckling. Spoon remaining glaze over slices of duckling, and sprinkle reserved pomegranate seeds on top of each serving. Serve with roasted parsnips and quinces. Makes 12 servings.