I kind of think Martha Ann is the same person as Mary A.
The LDS AF (and other family) records have this daughter Martha Ann, born 1841,
married
to Ranson Isaac Parmenter 30 Jul 1854 in Millersburg. The LDS records
don't have a daughter Mary A. who is on the 1850 census age 11.
Since the LDS don't have Mary and Martha isn't in the census,
I'm guessing they are the same person. The LDS data shows Martha as
marrying at age 13. If the age in the 1850 census is correct,
she would be a couple years older at least.