CREATE TABLE table_30931 ("No. overall" FLOAT, "No. for series" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "UK viewers  ( million ) " TEXT)

What episode number of the series is 'the coming of arthur (part 1)'?
SELECT "No. for series" FROM table_30931 WHERE "Title" = 'The Coming of Arthur (Part 1)'
SELECT "No. for series" FROM "table_30931" WHERE "Title" = 'The Coming of Arthur (Part 1)'