Table: bay_minesweeper
Columns: ship
original_pennant_number
builder
laid_down
launched
commissioned

Question: what builder launched 20 jun 1953?
SQL: SELECT "builder" FROM bay_minesweeper WHERE "launched" = '20 jun 1953'

Question: what is the commissioned date with laid down of 17 dec 1951?
SQL: SELECT "commissioned" FROM bay_minesweeper WHERE "laid_down" = '17 dec 1951'