Write a question about the following article: In Week 16, the Lions traveled west for a re-match with their division rival the Chicago Bears. The Lions entered the game having already clinched a playoff spot, thanks to the Washington Redskins' win over the Philadelphia Eagles the previous day.  Each team scored a touchdown in the first half. First Detroit's Reggie Bush ran one in from 13 yards out in the first quarter, then Chicago's Matt Forte caught an 11-yard pass from Jimmy Clausen late in the second quarter to tie it up at halftime. The Lions took the lead in the third quarter with a 39-yard field goal by Matt Prater, but the Bears went ahead with a 20-yard touchdown pass from Clausen to Alshon Jeffery. In the final quarter, Detroit scored 10 unanswered points for the victory: first a 17-yard touchdown run by Joique Bell, then a 30-yard field goal from Matt Prater. The win was the fifth of the season in which the Lions trailed entering the fourth quarter. It made the Lions 11-4 for the first time since 1991, and kept them undefeated against divisional opponents.

Question about the article:
How many yards was the shortest touchdown in the first half?