CREATE TABLE basketball_match (team_id NUMBER, school_id NUMBER, team_name CLOB, acc_regular_season CLOB, acc_percent CLOB, acc_home CLOB, acc_road CLOB, all_games CLOB, all_games_percent NUMBER, all_home CLOB, all_road CLOB, all_neutral CLOB)
CREATE TABLE university (school_id NUMBER, school CLOB, location CLOB, founded NUMBER, affiliation CLOB, enrollment NUMBER, nickname CLOB, primary_conference CLOB)

What are the average enrollment size of the universities that are founded before 1850?
SELECT AVG(enrollment) FROM university WHERE founded < 1850
SELECT AVG("enrollment") FROM "university" WHERE "founded" < 1850