CREATE TABLE table_27177 ("Year" TEXT, "Amiga demo" TEXT, "PC demo" TEXT, "C64 demo" TEXT, "Amiga intro" TEXT, "PC intro" TEXT)

Who won best amiga demo when tribes ( pulse & melon dezign) won best pc demo?
SELECT "Amiga demo" FROM table_27177 WHERE "PC demo" = 'Tribes ( Pulse & Melon Dezign)'
SELECT "Amiga demo" FROM "table_27177" WHERE "PC demo" = 'Tribes ( Pulse & Melon Dezign)'