Question: Michael Stich and Chanda Rubin, have which occupation in common?

Context paragraphs:
1997 State Farm Evert Cup – Doubles: Chanda Rubin and Brenda Schultz-McCarthy were the defending champions but only Rubin competed that year with Mary Joe Fernandez.

1998 Gerry Weber Open – Doubles: Karsten Braasch and Michael Stich were the defending champions, but Stich retired after the 1997 season and Braasch played with Jens Knippschild, but lost in the first roundEllis Ferreira and Rick Leach won the final 4–6, 6–4, 7–6 against John-Laffnie de Jager and Marc-Kevin Goellner.

1997 Australian Open – Women's Doubles: Chanda Rubin and Arantxa Sánchez Vicario were the defending champions, but competed this year with different partners.  Rubin teamed up with Brenda Schultz-McCarthy and were eliminated in third round, while Sánchez Vicario teamed up with Gigi Fernández and lost in semifinals.

2001 Bank of the West Classic – Doubles: Chanda Rubin and Sandrine Testud were the defending champions, but none competed this year.  Rubin decided to focus on the singles tournament, while Testud decided to rest after competing on the World Group Play-offs of the Fed Cup.

1995 Schweppes Tasmanian International – Doubles: Linda Harvey-Wild and Chanda Rubin were the defending champions but they competed with different partners that year, Harvey-Wild with Leila Meskhi and Rubin with Kristie Boogert.

1997 Bausch &amp; Lomb Championships – Doubles: Chanda Rubin and Arantxa Sánchez Vicario were the defending champions but they competed with different partners that year, Rubin with Brenda Schultz-McCarthy and Sánchez Vicario with Larisa Savchenko.

2010 French Open – Legends Under 45 Doubles: Paul Haarhuis and Cédric Pioline were the defending champion, but Haarhuis did not play this year.Pioline partnered up with Arnaud Boetsch, but they were eliminated by Goran Ivanišević and Michael Stich in the round-robin stage. Yevgeny Kafelnikov and Andriy Medvedev won in the final 6–1, 6–1 against Ivanisevic and Stich.

1993 Wimbledon Championships – Men's Doubles: John McEnroe and Michael Stich were the defending champions but only Stich competed that year with Wayne Ferreira.

Michael Stich: Michael Detlef Stich (born 18 October 1968) is a former professional tennis player from Germany.  He won the men's singles title at Wimbledon in 1991, the men's doubles titles at both Wimbledon and the Olympic Games in 1992, and was a singles runner-up at the 1994 US Open and the 1996 French Open.  Stich won 18 singles titles and 10 doubles titles.  His career-high singles ranking was World No. 2 in 1993.

Chanda Rubin: Chanda Rubin (born February 18, 1976) is an American tennis player.  Winning seven WTA Tour singles titles, she reached her highest ranking at World No. 6 on April 8, 1996, after reaching semifinals at the 1996 Australian Open.  Rubin is also former World No. 9 in doubles, winning the Australian Open in 1996 partnering with Arantxa Sánchez Vicario.

Supporting paragraphs: Michael Stich Chanda Rubin
Answer: tennis player