CREATE TABLE "table1_15861819_1" (
  "no_in_series" real,
  "no_in_season" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "originalairdate" text,
  "tv_broadcast" text
);

Question: Who wrote the "Head of State" episode?
SQL: SELECT "written_by" FROM "table1_15861819_1" WHERE "title"='\"Head of State\"';

Question: The "Head of State" episode was authored by which person?
SQL: SELECT "written_by" FROM "table1_15861819_1" WHERE "title"='\"Head of State\"';

Question: Who was the director of the episode "graduation day: class of 2105"?
SQL: SELECT "directed_by" FROM "table1_15861819_1" WHERE "title"='\"Graduation Day: Class of 2105\"';