CREATE TABLE table_18558 ("District" CLOB, "Incumbent" CLOB, "Party" CLOB, "First elected" FLOAT, "Result" CLOB, "Candidates" CLOB)

What year was first-elected for the row of Texas 2?
SELECT "First elected" FROM table_18558 WHERE "District" = 'Texas 2'
SELECT "First elected" FROM "table_18558" WHERE "District" = 'Texas 2'