CREATE TABLE table_30015 ("Province" TEXT, "Provincial capital" TEXT, "Commandery" TEXT, "Commandery capital" TEXT, "No. of counties" FLOAT)

when changsha is the commandery what is the commandery capital?
SELECT "Commandery capital" FROM table_30015 WHERE "Commandery" = 'Changsha 長沙'
SELECT "Commandery capital" FROM "table_30015" WHERE "Commandery" = 'Changsha 長沙'