The 12th Academy Awards ceremony was held on February 29, 1940, at the Ambassador Hotel in Los Angeles, with Bob Hope hosting. Gone With The Wind was nominated for 13 awards and won for Outstanding Production, Directing (Victor Fleming), Actress (Vivien Leigh), Art Direction (Lyle Wheeler), Cinematography (Color) (Ernest Haller and Ray Rennahan), and Film Editing (Hal Kern and James Newcom). Sidney Howard posthumously received the Writing (Screenplay) award, and production designer William Cameron Menzies received a special award for “outstanding use of color for the enhancement of dramatic mood in the production of Gone With The Wind.” In the Actress in Supporting Role category, Hattie McDaniel made history becoming the first African American to receive an Academy Award.
https://sites.utexas.edu/ransomcentermagazine/2016/02/26/hattie-mcdaniels-landmark-academy-awards-win/

Oscar’s First Black Winner Accepted Her Honor in a Segregated ‘No Blacks’ Hotel in L.A.~
http://www.hollywoodreporter.com/features/oscars-first-black-winner-accepted-774335
The Curious Case Of A Missing Academy Award~
http://www.npr.org/templates/story/story.php?storyId=100937570