CREATE TABLE table_26813 ("Episode no." FLOAT, "Airdate" TEXT, "Viewers" FLOAT, "BBC Three weekly ranking" TEXT, "Cable rank" TEXT)

What episode number had a cable ranking of 8?
SELECT MIN("Episode no.") FROM table_26813 WHERE "Cable rank" = '8'
SELECT MIN("Episode no.") FROM "table_26813" WHERE "Cable rank" = '8'