CREATE TABLE table_30018 ("Province" TEXT, "Provincial capital" TEXT, "Commandery" TEXT, "Commandery capital" TEXT, "No. of counties" FLOAT)

When zhang'an county is the commandery capital what is the province?
SELECT "Province" FROM table_30018 WHERE "Commandery capital" = 'Zhang''an County 章安縣'
SELECT "Province" FROM "table_30018" WHERE "Commandery capital" = 'Zhang\'an County 章安縣'