Simplify the following text for a Grade 13 native English-speaking person.
Original: In the political sense , the march was organized by a coalition of organizations and their leaders including : Randolph who was chosen as the titular head of the march , James Farmer ( president of the Congress of Racial Equality ) , John Lewis ( president of the Student Nonviolent Coordinating Committee ) , Martin Luther King , Jr. ( president of the Southern Christian Leadership Conference ) , Roy Wilkins ( president of the NAACP ) , Whitney Young ( president of the National Urban League ) .
Simplified: Some of the most important were James Farmer , ( president of the Congress of Racial Equality ) , John Lewis ( president of the Student Nonviolent Coordinating Committee ) , Martin Luther King , Jr. ( president of the Southern Christian Leadership Conference ) , Roy Wilkins ( president of the NAACP ) , and Whitney Young ( president of the National Urban League ) .