question: What is the place of birth of Margaret Casson's husband?
context: [["Stan Marks", ["Stan Marks is an Australian writer and journalist.", "He is the husband of Holocaust survivor Eva Marks."]], ["James Randall Marsh", ["James Randall Marsh( 1896- 1965) was an American artist and the husband of Anne Steele Marsh."]], ["George Matheson Murray", ["George Matheson Murray,( July 27, 1889 \u2013 August 19, 1961), known publicly as George Murray, was a publisher and politician in British Columbia in the first half of the 20th century.", "He played a role in the founding of the Boy Scouts of Canada.", "Murray is best known as the husband of Margaret Lally\" Ma\" Murray."]], ["Rick Casson", ["Richard L. Casson( born December 30, 1948 in Calgary, Alberta) is a Canadian politician.", "Casson was a member of the Conservative Party of Canada in the House of Commons of Canada, representing the riding of Lethbridge from 1997 to 2011."]], ["Jon Leach", ["Jonathan Leach( born April 18, 1973) is a former professional tennis player from the United States.", "He is the husband of Lindsay Davenport."]], ["Stan Rice", ["Stan Rice( November 7, 1942 \u2013 December 9, 2002) was an American poet and artist.", "He was the husband of author Anne Rice."]], ["Hugh Casson", ["Sir Hugh Maxwell Casson (23 May 1910, Hampstead, London \u2013 15 August 1999, Chelsea, London) was a British architect, interior designer, artist, and writer and broadcaster on 20th-century design.", "He was the director of architecture at the 1951 Festival of Britain on London's South Bank."]], ["Alfred Tozzer", ["Alfred Marston Tozzer( 4 July 1877 \u2013 5 October 1954) was an American anthropologist, archaeologist, linguist, and educator.", "His principal area of interest was Mesoamerican, especially Maya, studies.", "He was the husband of Margaret Castle Tozzer and father of figure skating champion Joan Tozzer."]], ["Andrew Upton", ["Andrew Upton( born 1 February 1966) is an Australian playwright, screenwriter, and director.", "He is the husband of actress Cate Blanchett."]], ["Margaret Casson", ["Margaret Casson, Lady Casson (26 September 1913 \u2013 12 November 1999) was an architect, designer and photographer, and the wife of architect Sir Hugh Casson."]]]
supporting_facts: [["Margaret Casson", 0], ["Hugh Casson", 0]]
evidences: [["Margaret Casson", "spouse", "Sir Hugh Casson"], ["Sir Hugh Maxwell Casson", "place of birth", "London"]]
answer: London