702.06  Deficiency decree; common-law suit to recover deficiency.--In all suits for the foreclosure of mortgages heretofore or hereafter executed the entry of a deficiency decree for any portion of a deficiency, should one exist, shall be within the sound judicial discretion of the court, but the complainant shall also have the right to sue at common law to recover such deficiency, provided no suit at law to recover such deficiency shall be maintained against the original mortgagor in cases where the mortgage is for the purchase price of the property involved and where the original mortgagee becomes the purchaser thereof at foreclosure sale and also is granted a deficiency decree against the original mortgagor.