CREATE TABLE table_13543 ("Class" TEXT, "Wheel arrangement" TEXT, "Fleet number ( s ) " TEXT, "Manufacturer" TEXT, "Year made" TEXT, "Quantity made" TEXT, "Quantity preserved" TEXT)

What wheel arrangement has a fleet number(s) of 45 46?
SELECT "Wheel arrangement" FROM table_13543 WHERE "Fleet number(s)" = '45–46'
SELECT "Wheel arrangement" FROM "table_13543" WHERE "Fleet number(s)" = '45–46'