CREATE TABLE table_18629 ("District" CLOB, "Incumbent" CLOB, "Party" CLOB, "First elected" FLOAT, "Result" CLOB, "Candidates" CLOB)

What district is incumbent robert l. mouton from?
SELECT "District" FROM table_18629 WHERE "Incumbent" = 'Robert L. Mouton'
SELECT "District" FROM "table_18629" WHERE "Incumbent" = 'Robert L. Mouton'