What is the date of vacancy when the manner of departure is sacked and the team is nejapa?
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
);
SELECT "date_of_vacancy" FROM "managerial_changes" WHERE "manner_of_departure"='sacked' AND "team"='nejapa';