CREATE TABLE table_65335 ("Vessel" TEXT, "Origin" TEXT, "Type" TEXT, "In service" FLOAT, "Unit" TEXT)

What is the highest In service for a vessel with a listed Unit of 12th minesweeper squadron?
SELECT MAX("In service") FROM table_65335 WHERE "Unit" = '12th minesweeper squadron'
SELECT MAX("In service") FROM "table_65335" WHERE "Unit" = '12th minesweeper squadron'