Oversight Commission on Presidential Capacity Act This bill establishes in the legislative branch an Oversight Commission on Presidential Capacity to determine whether the President is mentally or physically unable to discharge the powers and duties of office. The commission: (1) within 72 hours after Congress adopts a concurrent resolution directing it to do so, shall conduct a medical examination to determine if the President is temporarily or permanently impaired by physical illness or disability, mental illness, mental deficiency, or alcohol or drug use to the extent that he or she lacks sufficient understanding or capacity to execute the powers and duties of the office of President; and (2) within 72 hours after completing the examination, shall report its findings and conclusions to the Speaker of the House of Representatives and the President pro tempore of the Senate. Any refusal by the President to undergo such examination shall be taken into consideration by the commission in reaching a conclusion.