Question: What nationality was the woman who was first-seeded and won the singles title in The 1997 Porsche Tennis Grand Prix?

Context paragraphs:
2012 Porsche Tennis Grand Prix: The 2012 Porsche Tennis Grand Prix was a tennis tournament played on indoor clay courts.  It was the 35th edition of the Porsche Tennis Grand Prix, and was part of the Premier tournaments of the 2012 WTA Tour.  It took place at the Porsche Arena in Stuttgart, Germany, from April 23 through 29, 2012.

2014 Porsche Tennis Grand Prix: The 2014 Porsche Tennis Grand Prix is a tennis tournament played on indoor clay courts.  It is the 37th edition of the Porsche Tennis Grand Prix, and is part of the Premier tournaments of the 2014 WTA Tour.  It took place at the Porsche Arena in Stuttgart, Germany, from April 21 through 27, 2014.

Martina Hingis: Martina Hingis (born 30 September 1980) is a Swiss professional tennis player, a former world No. 1 singles player and currently ranked world No. 2 in doubles by the WTA.  She has spent a total of 209 weeks as the singles No. 1 and has won five Grand Slam singles titles, thirteen Grand Slam women's doubles titles, winning a calendar-year doubles Grand Slam in 1998, and seven Grand Slam mixed doubles titles; for a combined total of twenty-five major titles.  In addition, she has won the season-ending WTA Championships two times in singles and three times in doubles, and an Olympic silver medal.

2007 Porsche Tennis Grand Prix: The 2007 Porsche Tennis Grand Prix was a tennis tournament played on indoor hard courts.  It was the 30th year of Porsche Tennis Grand Prix, and was part of the Tier II Series of the 2007 WTA Tour.  It took place at the Porsche Arena in Stuttgart, Germany, from October 1 through October 7, 2007

1997 Porsche Tennis Grand Prix: The 1997 Porsche Tennis Grand Prix was a women's tennis tournament played on indoor hard courts at the Filderstadt Tennis Club in Filderstadt in Germany that was part of Tier II of the 1997 WTA Tour.  It was the 20th edition of the tournament and was held from 6 October through 12 October 1997.  First-seeded Martina Hingis won the singles title, her second consecutive at the event.

2015 Porsche Tennis Grand Prix: The 2015 Porsche Tennis Grand Prix was a women's tennis tournament played on indoor clay courts.  It was the 38th edition of the Porsche Tennis Grand Prix, and part of the Premier tournaments of the 2015 WTA Tour.  It took place at the Porsche Arena in Stuttgart, Germany, from 20 April through 26 April 2015.  Unseeded Angelique Kerber won the singles title.

2008 Porsche Tennis Grand Prix: The 2008 Porsche Tennis Grand Prix was a tennis tournament played on indoor hard courts.  It was the 31st edition of the Porsche Tennis Grand Prix, and was part of the Tier II Series of the 2008 WTA Tour.  It took place at the Porsche Arena in Stuttgart, Germany, from September 27 through October 5, 2008.

2016 Porsche Tennis Grand Prix: The 2016 Porsche Tennis Grand Prix was a women's tennis tournament played on indoor clay courts.  It was the 39th edition of the Porsche Tennis Grand Prix, and part of the Premier tournaments of the 2016 WTA Tour.  It took place at the Porsche Arena in Stuttgart, Germany, from 18 April through 24 April 2016.

2009 Porsche Tennis Grand Prix: The 2009 Porsche Tennis Grand Prix is a tennis tournament played on indoor clay courts.  It is the 32nd edition of the Porsche Tennis Grand Prix, and is part of the Premier tournaments of the 2009 WTA Tour.  It will take place at the Porsche Arena in Stuttgart, Germany, from April 27 through May 3, 2009.

2013 Porsche Tennis Grand Prix: The 2013 Porsche Tennis Grand Prix was a tennis tournament played on indoor clay courts.  It was the 36th edition of the Porsche Tennis Grand Prix, and was part of the Premier tournaments of the 2013 WTA Tour.  It took place at the Porsche Arena in Stuttgart, Germany, from April 22 through 28, 2013.

Supporting paragraphs: 1997 Porsche Tennis Grand Prix Martina Hingis
Answer: Swiss