In Oracle, the POWER function raises a value to the specified power. MariaDB also provides the POWER function, so no conversion is required.
Oracle:
-- Raise 2 to 3 power SELECT POWER(2, 3) FROM dual; # 8
MariaDB:
-- Raise 2 to 3 power SELECT POWER(2, 3); # 8
For more information, see Oracle to MariaDB Migration.