CREATE TABLE table_25661 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Prod. code" TEXT, "Viewers  ( millions ) " TEXT)

when the number of spectator are 5.28 millions, which is the smallest number of the episode in series?
SELECT MIN("No. in series") FROM table_25661 WHERE "Viewers (millions)" = '5.28'
SELECT MIN("No. in series") FROM "table_25661" WHERE "Viewers (millions)" = '5.28'