CREATE TABLE table_name_66 (population_2006_census INT, local_government_area VARCHAR, rank VARCHAR)

What was the 2006 population for the local government area of alexandrina council whose rank was smaller than 19?
SELECT AVG(population_2006_census) FROM table_name_66 WHERE local_government_area = "alexandrina council" AND rank < 19
SELECT AVG("population_2006_census") FROM "table_name_66" WHERE "alexandrina council" = "local_government_area" AND "rank" < 19