My answer:
>!27 seconds. 

Because:  
>!Because one person can no longer overtake another if the other has already overtaken him, Neeraj can only be second place during the lead of **two consecutive people**. Why two? Let's assume he started at position 2. For 13 seconds, no overtakings take place. Then, former position 3 (Harsh) overtakes Neeraj and Ashish, while Ashish falls behind you. Neeraj is now still position 2 for the next period (14 seconds). But now Neeraj can't stay on position 2 because he cannot overtake Harsh anymore, while Devesh overtakes them both. He will never get to position 2 any more. 
>!The longest period of two consecutive leaders is **27 seconds** (Ashish and Harsh), and that will be my answer.