CREATE TABLE table_18157 ("District" CLOB, "Incumbent" CLOB, "Party" CLOB, "First elected" CLOB, "Results" CLOB, "Candidates" CLOB)

When was Chaka Fattah first elected in the Pennsylvania 2 district?
SELECT "First elected" FROM table_18157 WHERE "District" = 'Pennsylvania 2'
SELECT "First elected" FROM "table_18157" WHERE "District" = 'Pennsylvania 2'