user: Question: What was the earliest year Þorvaldur Ásgeirsson Lovísa Sigurðardóttir won mixed doubles
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 MIN("Year") FROM "Table" WHERE "Mixed doubles" = 'Þorvaldur Ásgeirsson Lovísa Sigurðardóttir';