Table: election_results_1978_4
Columns: district
incumbent
party
first_elected
result
candidates

Question: Which district is republican?
SQL: SELECT "district" FROM election_results_1978_4 WHERE "party" = 'Republican'

Question: Name the result when the incumbent was george h. mahon
SQL: SELECT "result" FROM election_results_1978_4 WHERE "incumbent" = 'George H. Mahon'

Question: What was the incumbent of texas 3?
SQL: SELECT "incumbent" FROM election_results_1978_4 WHERE "district" = 'Texas 3'

Question: What was the incumbent for texas 19?
SQL: SELECT "incumbent" FROM election_results_1978_4 WHERE "district" = 'Texas 19'