Task: Text to Code
Input (English): What is the semester which most student registered in? Show both the name and the id.
Output (English): SELECT T1.semester_name ,  T1.semester_id FROM Semesters AS T1 JOIN Student_Enrolment AS T2 ON T1.semester_id  =  T2.semester_id GROUP BY T1.semester_id ORDER BY count(*) DESC LIMIT 1