CREATE TABLE table_63436 ("Processor" TEXT, "Model" TEXT, "Clock speed  ( MHz ) " FLOAT, "L1 cache  ( bytes ) " TEXT, "Introduced" TEXT, "Discontinued" TEXT)

With April 1986 as the introduced, what is the least clock speed (MHz)?
SELECT MIN("Clock speed (MHz)") FROM table_63436 WHERE "Introduced" = 'april 1986'
SELECT MIN("Clock speed (MHz)") FROM "table_63436" WHERE "Introduced" = 'april 1986'