CREATE TABLE table_21434618_1 (team__number1 VARCHAR2, team__number2 VARCHAR2)

which team #1 played again chalkida
SELECT team__number1 FROM table_21434618_1 WHERE team__number2 = "Chalkida"
SELECT "team__number1" FROM "table_21434618_1" WHERE "Chalkida" = "team__number2"