TIL: continue in sed(1) is really not n; but rather { p; d; } (at least in simple enough cases).
{
# Let's construct a single long input line
# from multiple short lines that fit better
# on the web page.
tr -d \\n <<-EOF
207.46.13.105 - - [29/Jan/2020:17:23:25 +0200]
"GET /cgi-bin/man-cgi?hier+7 HTTP/1.1"
200 61152 "-" "Mozilla/5.0 (compatible;
bingbot/2.0; +http://www.bing.com/bingbot.htm)"
EOF
echo
} |
sed -e '
s/^[^"]*"//
s/".*$//
/^.* HTTP\/\([0-9]\.[0-9]\)$/ { s//\1/; p; d; }
s/^.*$/0.9/
'