Formateo de cadenas usando LISTAGG en Oracle. Comillas simples de escape ` ' `

Podrías usar:

SELECT LISTAGG('''' || student_name || '''',',') 
       WITHIN GROUP (ORDER BY student_name)
FROM students;

o usando ENQUOTE_LITERAL función:

SELECT LISTAGG(DBMS_ASSERT.ENQUOTE_LITERAL(student_name),',') 
       WITHIN GROUP (ORDER BY student_name) AS r
FROM students;

Demostración de DBFiddle