CREATE TABLE table_27181 ("Year" TEXT, "Amiga demo" TEXT, "PC demo" TEXT, "C64 demo" TEXT, "Amiga intro" TEXT, "PC intro" TEXT)

What won best pc demo when tower power (camelot) won best c64 demo?
SELECT "PC demo" FROM table_27181 WHERE "C64 demo" = 'Tower Power (Camelot)'
SELECT "PC demo" FROM "table_27181" WHERE "C64 demo" = 'Tower Power (Camelot)'