Since David G. Dungan b: abt 1813, d: bef 1850 is the son of Benjamin Dungan & Margaret Mitchell and he married Lydia Chambers 18 Feb 1836, his children were: 1. Rebecca S. Dungan, b: abt 1837 IN. Married John Miller. 2. Margaret A. Dungan, b: abt 1842 IN. Never Married. AND probably but not proven 3. Mary Jane Dungan, b: abt 1839 IN. May have married John White.
Rebecca & Margaret I have definite proof through census records. Lydia & Margaret lived with Rebecca & her husband and then with their son Benjamin. In the 1880 census, Lydia is listed as Benjamin's (Frank) Grandmother and Margaret as Aunt. Since Benjamin Miller was going by Frank in that 1880 census, I've wondered if his name was perhaps Benjamin Franklin Miller.
Let me know if you find the Joseph Dungan, who married Rebecca Chamber, in your database. I'd like to figure out who he was the son of. I'd probably focus on parents who were born in Pennsylvania but had some of their children in Ohio circa early to mid 1800's, since Joseph was born either in 1813 or 1814 in Ohio.