Heat oil in a large soup pot and add the chopped onion, carrot, celery and pepperoni. Cook stirring occasional for 5-7 minutes. Pour in the white wine and reduce to almost dry. Next add the chopped tomatoes and drained beans and mix well. Pour in the broth and water and bring to a simmer. Simmer for 15-20 minutes. Stir in the fresh oregano and cooked Ditalini pasta. Serve with grated parmesan and a dollop of pesto.