Mildred Hart was born 1902. She was the daughter of Felix Stanley Hart and Sarah Graham.  She married William Howard Duvall in 1928. The following brief article ran in the Seattle Daily Times ahead of the ceremony:
Miss Hart and Navy Officer to Wed Tomorrow
The marriage of Miss Mildred Hart, daughter of Mrs. Hart and the late F. Stanley Hart, to Lieutenant William Howard Duvall, son of Mr. and Mrs. A. L. Duvall of Alexandria, Va., will take place tomorrow evening at 8:30 o'clock at the Church of the Epiphany.
Miss Hart, who will be given in marriage by Mr. O.H. Carpenter, will have her sister, Mrs. Harold Bailey Prescott, as her only attendant. Ensign C.A. Villadou will be best man and Lieutenant J. R. Pahl and Ensigns L. H. Martin, R. E. Fenton, and M.A. Nation will be ushers.
A small reception at the home of Mr. and Mrs. J.J. Jennelle will follow the ceremony. 
Mildred Hart Duvall died in 1985 in Fairfax, Virginia , and is buried at Arlington Cemetery with her husband. 
↑ "United States Census, 1920," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MHNR-XM7 : accessed 19 September 2017), Mildred Hart in household of Felix S Hart, Seattle, King, Washington, United States; citing ED 194, sheet 10B, line 60, family 119, NARA microfilm publication T625 (Washington D.C.: National Archives and Records Administration, 1992), roll 1928; FHL microfilm 1,821,928.
↑ "United States Social Security Death Index," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:JBW9-L3R : 20 May 2014), Mildred Duvall, Mar 1985; citing U.S. Social Security Administration, Death Master File, database (Alexandria, Virginia: National Technical Information Service, ongoing).
↑ Find A Grave, database and images (https://new.findagrave.com : accessed 19 September 2017), memorial page for Mildred Hart Duvall (26 Aug 1901–11 Mar 1985), Find A Grave Memorial no. 132277693, citing Arlington National Cemetery, Arlington, Arlington County, Virginia, USA ; Maintained by David McInturff (contributor 47179039) .