Context: Coming off their home win over the Jets, the Bengals stayed at home for an AFC North clash with the Pittsburgh Steelers.  In the first quarter, Cincinnati struck first with kicker Shayne Graham getting a 31-yard field goal.  However, the Steelers responded with QB Ben Roethlisberger completing a 21-yard TD pass to WR Hines Ward.  In the second quarter, the Bengals struggled as Roethlisberger and Ward hooked up with each other again on a 6-yard TD pass.  Cincinnati answered with Graham kicking a 20-yard field goal.  Pittsburgh ended the first half with RB Willie Parker getting a 1-yard TD run. After a scoreless third quarter, the Bengals tried to come back as QB Carson Palmer completed a 9-yard TD pass to WR T. J. Houshmandzadeh in the fourth quarter. Pittsburgh sealed the win with kicker Jeff Reed nailing a 40-yard field goal.

Question: Who threw the longest TD pass?

Answer:
Ben Roethlisberger