You didn't say much about what you found on the 1900 census on this couple.From age of their children and birth locations I figured they must be in GA in 1880.
1880 census Trion, Chatooga Co, GA:
Category: Name;Relationship to head of household; Marital Status; Gender; Race; Age; Birthplace; Occupation; Father's Birthplace; Mother's Birthplace.
John P. LEDBETTERSelfMMaleW29TNFarm LaborerTNTN
Margaret C. LEDBETTERWifeMFemaleW27GAKeeping HouseTNGA
Lee U. LEDBETTERDauSFemaleW1GATNGA
John THOMASOtherSMaleW15GAFarm LaborerTNGA
Margaret C. is probably Clara on 1990 census, and Lee U. probably the Eula on the 1900 census.
Same page, are these the parents of John?Both born in TN:
Phebe LEDBETTERWifeMFemaleW58TNKeeping HouseTNTN
Sarah LEDBETTERDauSFemaleW32TNAt HomeTNTN
James E. LEDBETTERSonSMaleW24TNFarm LaborerTNTN
Mary L. LEDBETTERDauSFemaleW22TNAt HomeTNTN
Ellen M. LEDBETTERDauSFemaleW18TNAt HomeTNTN
Dovie M. LEDBETTERDauSFemaleW9ALTNTN
If they are, 1870 census Talladega Co, AL:
Ledbetter, William, 56, b TN
" Phebe, 44, b TN
" Sallie, 22, b TN (note older Sally in 1860 census below)
" John, 19, b TN (your John?)
" Elizabeth, 16, b TN
" James, 14, b TN
" Mary L., 12, b TN
" Martha E., 9, b TN
" Tennessee (?), 5, b AL
" Margaret D., 1/12, b AL - born in May
1860 Bradley Co, TN:
Ledbetter, Wm, 45, b TN
" Phebe, 36, b TN
" Andrew J., b TN
" Sarah, 13, b TN
" Nancy, 11, b TN
" John, 9, b TN (your John?)
" L_____, 5, b TN
" James, 4, b TN
" Mary, 3, b TN
" Sally, 86, b TN - is this the mother of William???
If this is your family, check out the Bradley Co, TN GenWeb site.Among many good things they have a surname index for 1850 census and there are 2 "Leadbetter" names listed (same spelling that showed up on the 1900 census).I would check land records for William, and probate for any older Leadbetter, see if William shows up as an heir.Lots of good stuff on there.
Happy Hunting (^_^)