CREATE TABLE table_name_50 (tyre VARCHAR, pole_position VARCHAR, race VARCHAR)

In the Canadian Grand Prix, what tyre was used when Jacky Ickx held pole position?
SELECT tyre FROM table_name_50 WHERE pole_position = "jacky ickx" AND race = "canadian grand prix"
SELECT "tyre" FROM "table_name_50" WHERE "canadian grand prix" = "race" AND "jacky ickx" = "pole_position"