user: Question: Who won mixed doubles the years Einar Jónsson Wagner Walbom won mens doubles and Wagner Walbom won mens singles
Columns: ['Year', 'Mens singles', 'Womens singles', 'Mens doubles', 'Womens doubles', 'Mixed doubles']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1949.0, 'Einar Jónsson', 'no competition', 'Friðrik Sigurbjörnsson Guðjón Einarsson', 'no competition', 'no competition']
SQL:

assistant: SELECT "Mixed doubles" FROM "Table" WHERE "Mens doubles" = 'Einar Jónsson Wagner Walbom' AND "Mens singles" = 'Wagner Walbom';