user: Question: On what date was Keiichi Ubukata the mediator and Mitsuko Mori the red team host?
Columns: ['Kōhaku #', 'Date', 'Red Team Host', 'White Team Host', 'Mediator', 'Winning Team']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, '3 January 1951', 'Michiko Katō', 'Shuuichi Fujikura', 'Masaharu Tanabe', 'White']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Mediator" = 'Keiichi Ubukata' AND "Red Team Host" = 'Mitsuko Mori';