CREATE TABLE table_name_16 (margin_of_victory VARCHAR2, runner_s__up VARCHAR2)

By how many strokes did Lema beat Jack Nicklaus?
SELECT margin_of_victory FROM table_name_16 WHERE runner_s__up = "jack nicklaus"
SELECT "margin_of_victory" FROM "table_name_16" WHERE "jack nicklaus" = "runner_s__up"