CREATE TABLE table_18702 ("District" CLOB, "Incumbent" CLOB, "Party" CLOB, "First elected" FLOAT, "Result" CLOB, "Candidates" CLOB)

what's the district with candidates being john e. rankin (d) unopposed
SELECT "District" FROM table_18702 WHERE "Candidates" = 'John E. Rankin (D) Unopposed'
SELECT "District" FROM "table_18702" WHERE "Candidates" = 'John E. Rankin (D) Unopposed'