CREATE TABLE table_18107 ("District" CLOB, "Incumbent" CLOB, "Party" CLOB, "First elected" FLOAT, "Results" CLOB, "Candidates" CLOB)

Which district is Joe Moakley?
SELECT "District" FROM table_18107 WHERE "Incumbent" = 'Joe Moakley'
SELECT "District" FROM "table_18107" WHERE "Incumbent" = 'Joe Moakley'