CREATE TABLE table_31908 ("Round" FLOAT, "Circuit" CLOB, "Date" CLOB, "Pole Position" CLOB, "Fastest Lap" CLOB, "Winning Driver" CLOB, "Winning Team" CLOB)

Name the winning driver for mobilecast impul and twin ring motegi
SELECT "Winning Driver" FROM table_31908 WHERE "Winning Team" = 'mobilecast impul' AND "Circuit" = 'twin ring motegi'
SELECT "Winning Driver" FROM "table_31908" WHERE "Circuit" = 'twin ring motegi' AND "Winning Team" = 'mobilecast impul'