What is the smallest time margin the Tour de France has been won by?

Explanation

The main competition in Tour de France is the overall placement where all the riders' times on all stages are added up. The smallest time margin a Tour de France has been won by was just 8 seconds. That was back in 1989, where the American Greg LeMond won ahead of Laurent Fignon. Experts have since calculated that Greg LeMond won on better aerodynamics, as Fignon rode his time trial on a normal bike with his characteristic pony tail blowing in the wind.