Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Position | best year | best 2-year period | best 3-year period | best 5-year period | best 10-year period | best 15-year period |
| --- | --- | --- | --- | --- | --- | --- |
| 1.0 | Fischer | Fischer | Fischer | Fischer; Kasparov | Fischer; Capablanca | Capablanca |
| 2.0 | Kramnik | Kramnik; Capablanca; Kasparov | Capablanca; Kasparov | Fischer; Kasparov | Fischer; Capablanca | Karpov; Kramnik |
| 3.0 | Kasparov | Kramnik; Capablanca; Kasparov | Capablanca; Kasparov | Capablanca | Kramnik | Karpov; Kramnik |
| 4.0 | Botvinnik | Kramnik; Capablanca; Kasparov | Smyslov | Kramnik; Botvinnik | Kasparov | Smyslov; Kasparov |
| 5.0 | Capablanca | Karpov; Smyslov | Botvinnik | Kramnik; Botvinnik | Karpov; Smyslov | Smyslov; Kasparov |
| 6.0 | Karpov | Karpov; Smyslov | Kramnik | Smyslov | Karpov; Smyslov | Fischer |
| 7.0 | Smyslov; Tal | Botvinnik; Alekhine | Karpov | Karpov; Lasker | Botvinnik; Spassky | Botvinnik; Spassky; Petrosian |
| 8.0 | Smyslov; Tal | Botvinnik; Alekhine | Spassky; Lasker | Karpov; Lasker | Botvinnik; Spassky | Botvinnik; Spassky; Petrosian |
| 9.0 | Petrosian | Anand | Spassky; Lasker | Alekhine; Anand | Anand | Botvinnik; Spassky; Petrosian |
| 10.0 | Euwe | Tal; Spassky | Anand | Alekhine; Anand | Lasker; Petrosian | Anand |
| 11.0 | Spassky | Tal; Spassky | Petrosian | Petrosian; Spassky | Lasker; Petrosian | Tal |
| 12.0 | Alekhine; Anand | Lasker; Euwe | Tal; Alekhine | Petrosian; Spassky | Tal; Alekhine | Alekhine; Lasker |
| 13.0 | Alekhine; Anand | Lasker; Euwe | Tal; Alekhine | Euwe; Tal | Tal; Alekhine | Alekhine; Lasker |
| 14.0 | Lasker | Petrosian | Euwe | Euwe; Tal | Euwe | Euwe |
| 15.0 | Morphy | Morphy | Morphy | Steinitz | Steinitz | Steinitz |
| 16.0 | Steinitz | Steinitz | Steinitz | — | — | — |
Question:
Which Position has a best 3-year period of petrosian?
Answer:
11.0