CREATE TABLE table_6064 ("Year" CLOB, "League" CLOB, "Season" CLOB, "Play-Off" CLOB, "Baltic" CLOB, "Events" CLOB, "European" CLOB)

Which Play-Off has Events of , and a Season of a-6?
SELECT "Play-Off" FROM table_6064 WHERE "Events" = '–' AND "Season" = 'a-6'
SELECT "Play-Off" FROM "table_6064" WHERE "Events" = '–' AND "Season" = 'a-6'