Why Computer Science students learn Digital Logic Design? Is there any relationship between a computer science student and DLD course? I am studying BSE and we are studying DLD in my second semester. We've learned so many things about DLD but nothing is related to the CS or SE. It's all about gates and related to Electrical Engineer. 
Is there any need of DLD in Software Engineering? While the main thing which is concern for us is Programming Languages and Computers System?
Logic is used A lot in programming. 

There is little difference between hardware and software. It is just an implementation detail. The choice of what goes where is a balance between cost and speed, but where ever it goes it is just logic: if you implement it in Python, C♯, assembler, HTML, electronics, or mechanical.