user: Question: what is the date for traction type Electric with Calgary location?
Columns: ['Name of System', 'Location', 'Traction Type', 'Date (From)', 'Date (To)']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Calgary Municipal Railway', 'Calgary', 'Electric', '5 Jul 1909 25 May 1981', '29 Dec 1950 -']
SQL:

assistant: SELECT "Date (From)" FROM "Table" WHERE "Traction Type" = 'Electric' AND "Location" = 'Calgary';