Coming off their dominating Monday Night performance against the Ravens, the Steelers stayed at home for Round 2 of the 2007 Rust Belt series against the Cleveland Browns.  In the first quarter, Pittsburgh trailed early as Browns QB Derek Anderson completed a 4-yard TD pass to TE Kellen Winslow.  The Steelers managed to get a 28-yard field goal from kicker Jeff Reed.  In the second quarter, Cleveland increased its lead with Anderson completing a 2-yard TD pass to FB Lawrence Vickers, while Pittsburgh only managed to have Reed kick a 35-yard field goal.  Afterwards, the Browns continued their fast start with Anderson completing a 16-yard TD pass to WR Braylon Edwards.  The Steelers drove into the red zone once again but settled for a 30-yard field goal from Reed.  Both teams scored thrice in the first half; Cleveland led 21-9. In the third quarter, Pittsburgh began to come back as QB Ben Roethlisberger completed a 12-yard TD pass to WR Hines Ward for the only score of the period.  In the fourth quarter, the Steelers took the lead with Roethlisberger getting a career-best 30-yard TD run.  Cleveland WR/KR Joshua Cribbs returned the ensuing kickoff 100&#160;yards for a touchdown.  Pittsburgh on their next drive retook the lead with Roethlisberger completing a 2-yard TD pass to TE Heath Miller.  The Browns tried to force overtime with a late field goal, but kicker Phil Dawson's 53-yard attempt came up short with 6&#160;seconds left. With their ninth straight win over Cleveland, the Steelers improved to 7-2 increasing the all-time series to 57-55.
Question: How many points did Cleveland lead by at halftime?
Answer: 12