Question: Which director is also a producer, David Nixon or Lee Grant?

Context paragraphs:
David Nixon (footballer): David Nixon (born 9 July 1988 in Paisley, Scotland) is a Scottish defender footballer for Airdrie United.

Tell Me a Riddle (film): Tell Me a Riddle is a 1980 American drama film directed by Lee Grant.  The screenplay by Joyce Eliason and Alev Lytle is based on the 1961 O'Henry award novella from Tillie Olsen's collection of short stories of the same name.  This is Grant's first film as director, and two more such films followed: "Down and Out in America" and "Staying Together".

Lee Grant: Lee Grant (born Lyova Haskell Rosenthal; October 31, during the mid 1920s) is an American actress and film director.

Lee Grant (New Zealand actress): Leonara Elizabeth Grant {'1': ", '2': ", '3': ", '4': "} (3 August 1931 – 22 July 2016), known professionally as Lee Grant or Miss Lee Grant, was an English-born New Zealand actress and singer.

Staying Together (film): Staying Together is a 1989 American comedy-drama film directed by Lee Grant and produced by Joseph Feury (Grant's husband) and Milton Justice.  The film stars Sean Astin, Stockard Channing, Melinda Dillon, Levon Helm (of The Band), Dermot Mulroney, Tim Quill, and Daphne Zuniga.  Grant's daughter, Dinah Manoff appears briefly making this the only film project (excluding TV Movies) to involve Grant, Feury and Manoff.

David Nixon (American football): David Nixon (born March 16, 1985 in College Station, Texas) is a former American football linebacker.  He was undrafted in the 2009 NFL Draft to the Oakland Raiders.  He played college football at Brigham Young University.

David Nixon (choreographer): David Nixon OBE is a Canadian dance choreographer.

David Nixon (magician): David Nixon (29 December 1919 – 1 December 1978) was an English magician and television personality.  At the height of his career, Nixon was the best-known magician in the UK.

David Nixon (director): David Nixon is an American film director and film producer.  He is the director and producer of "Letters to God" and a co-producer and assistant director of "Fireproof" and "Facing the Giants".

Letters to God: Letters to God is a 2010 Christian drama film directed by David Nixon and starring Robyn Lively, Jeffrey Johnson, Tanner Maguire, Michael Bolten and Bailee Madison.  The story was written by Patrick Doughtie about his son Tyler, with the screenplay penned by Doughtie, Art D'Alessandro, Sandra Thrift and Cullen Douglas.  The story took place in Nashville, Tennessee, but the movie was filmed in the Orlando, Florida area.

Supporting paragraphs: David Nixon (director) Lee Grant
Answer: David Nixon