CREATE TABLE table_204_42 (id DECIMAL, "season" DECIMAL, "level" TEXT, "division" TEXT, "section" TEXT, "position" TEXT, "movements" TEXT)

when was the first season that the team was in tier 6 ?
SELECT "season" FROM table_204_42 WHERE "level" = 'tier 6' ORDER BY "season" LIMIT 1
SELECT "season" FROM "table_204_42" WHERE "level" = 'tier 6' ORDER BY "season" NULLS FIRST LIMIT 1