Combine 1/2 cup onion, wine, and next 3 ingredients in a Dutch oven over medium-high heat; bring to a boil. Cover and cook 2 minutes or until clams open; discard any unopened shells. Strain through a cheesecloth-lined sieve over a bowl, reserving cooking liquid and clams. Remove meat from clams; chop. Discard shells.
Wipe pan clean. Melt butter in pan. Add bacon; sauté 3 minutes. Stir in 1 cup onion, potato, celery, and red pepper; sauté 4 minutes. Stir in flour; cook 1 minute. Stir in cooking liquid and 1/3 cup water; bring to a boil. Cover and reduce heat; simmer 30 minutes, stirring occasionally. Stir in clams, half-and-half, and milk; cook 1 minute or until heated. Stir in herbs.