CREATE TABLE "managerial_changes" (
  "team" text,
  "outgoing_manager" text,
  "manner_of_departure" text,
  "date_of_vacancy" text,
  "replaced_by" text,
  "date_of_appointment" text,
  "position_in_table" text
);

Question: Who came as a replacement in Sheffield United?
SQL: SELECT "replaced_by" FROM "managerial_changes" WHERE "team"='Sheffield United';

Question: When was the new manager of the team on 21st position appointed?
SQL: SELECT "date_of_appointment" FROM "managerial_changes" WHERE "position_in_table"='21st';

Question: What was Gary Megson's manner of departure?
SQL: SELECT "manner_of_departure" FROM "managerial_changes" WHERE "outgoing_manager"='Gary Megson';

Question: When did the old manager vacate his position in Plymouth Argyle?
SQL: SELECT "date_of_vacancy" FROM "managerial_changes" WHERE "team"='Plymouth Argyle';